Month-long lunar days passed, while the two men ranged over a segment of the hidden hemisphere. They trod plains and crater-walls unsullied by human feet before; they took photographs to be sold to the Lunar Topographical Commission; they located deposits of radioactive metals, which could be registered for investigation by an assaying party, and for possible royalties. Periodically they visited scattered supply stations, and then set out once more. Such a life had its poisons even for Brinker and Copeland, who were braced for meeting the unknown and the strange. Living in space suits for weeks at a time; smelling their own unwashed bodies; slipping an arm out of a heavy sleeve to draw food through a little airlock in their armor's chestplate; knowing, in spite of effective insulation, that the heat of day exceeded the boiling point of water, and that the cold of the protracted night, when usually they continued their explorations with the aid of ato-lamps, hovered at the brink of absolute zero--all those things had a harsh effect on nervous-systems. They found two human corpses. One had been crushed in a long fall, his spacesuit ripped open; he was a blackened mummy. The other was a freckled youth, coffined in his armor. Failure of its air-rejuvenator unit had caused asphyxia. What you did for guys like this was collect their credentials for shipment home. Copeland also found a Martian--inside its transparent version of a spacesuit, for the ancient Moon had been much the same as now. The being was dead, of course. Its brain-case had been a sac; its tentacles were like a snarl of age-hardened leather thongs. Lying near it was an even greater rarity--the remains of a different sort of monster from the planet that had been literally exploded in a war with Mars, to form the countless fragments that were the asteroids. That much of remote history was already known from the research-expeditions that had gone out to the Red Planet, and beyond. The queer, advanced equipment of these two beings from two small, swift-cooling worlds--which had borne life early, and whose cultures had rivalled briefly for dominance of the solar system until they had wiped each other out those fifty million years ago--lay scattered near them. It was still as bright and new as yesterday, preserved by the Moon's vacuum: Cameras, weapons, instruments--rich loot, now, to be sold to labs that sought to add the technology of other minds to human knowledge. For a year, things went well. The names, BRINKER and COPELAND, footprinted into the lunar dust, helped build the new reputation that Brinker wanted. Copeland and he were a hard-working team; they covered more ground than any other Moon explorers.